1. Field of the Invention
The present invention relates to an electrooptical apparatus such as an active matrix liquid crystal apparatus driven by thin-film transistors (hereinafter also referred to as TFTs), and also to a method of producing such an electrooptical apparatus. More particularly, the present invention relates to an electrooptical apparatus such as a liquid crystal apparatus suitable for use in a liquid crystal projector, and including peripheral circuits such as a data line driving circuit and a scanning line driving circuit, wherein a light blocking film is disposed under each TFT. The present invention further relates to a method of producing such an electrooptical apparatus.
2. Description of Related Art
In conventional liquid crystal apparatus having built-in peripheral circuits, peripheral circuits such as a data line driving circuit, a scanning line driving circuit, and a sampling circuit are formed on a TFT array substrate, which is one of two substrates between which a liquid crystal is disposed. In general, these peripheral circuits are produced using the same production process as that for producing TFTs for switching an image signal applied to pixel electrodes provided in respective pixels (hereinafter such TFTs will also be referred to as pixel TFTs) so as to achieve a high production efficiency.
On the TFT array substrate, there are provided a great number of data lines and scanning lines in an image displaying area in contact with the liquid crystal, wherein these data lines and scanning lines cross each other at different layer levels. Input/output wirings connected to peripheral circuits are disposed in a sealing area, outside the image displaying area and in contact with a scaling material for enclosing a liquid crystal, and in a peripheral area outside the sealing area. More specifically, leading wirings which extend from the data lines, the scanning lines, and the capacitance lines, and which serve as the input/output wirings for the peripheral circuits, are disposed in the sealing area and image signal lines, control signal lines, power supply lines, clock signal lines, and other signal lines, connected to external input terminals, and are disposed in the peripheral area.
In particular, in a liquid crystal apparatus having a sampling circuit as a peripheral circuit, when an image signal is supplied to an image signal line via an external input terminal, the image signal is sampled, from one data line to another, by sampling switches of the sampling circuit, in response to a sampling circuit driving signal output with predetermined timing from the data line driving circuit.
Because the image signal line is a signal line used to supply the image signal itself, which defines the voltage applied to the liquid crystal, it is extremely important that the image signal line has a low electric resistance and a small time constant to prevent degradation in the picture quality. To this end, the image signal line is generally formed of a thin metal film such as an aluminum film which has the lowest resistivity of all thin films used in the active matrix TFT liquid crystal apparatus, and which is also used to form data lines.
On the other hand, there are no currently available techniques which can be used to form the scanning lines of a thin metal film or a thin metal silicide film, because existing techniques would be subject to the problem that the scanning lines would peel off during a high-temperature process performed after the formation of the scanning lines. For the above reason, the scanning lines are generally formed of a thin polysilicon film. The wiring formed of a thin polysilicon film has as high a resistance as several ten times that of an wiring formed of a thin metal film, and thus has a correspondingly high time constant. For the above reason, if the image signal line was formed of a thin polysilicon film, degradation in the image quality would occur depending on the resistance and the time constant of the wiring employed as the image signal line. In practice, to avoid the above problem, the image signal line is formed of a thin metal film, as described above.
In the above-described type liquid crystal apparatus including the peripheral circuit, if there is only one image signal line, it is possible to form the image signal line with an wiring formed of a thin metal film at the same single layer lever (produced in the same process) over the entire path from an external circuit connecting terminal disposed at an end of a substrate to respective sampling switches of the sampling circuit. However, in the case where a plurality of image signal lines are required to transmit image signals serial-parallel converted into a plurality of phases so as to handle high-frequency driving operation in the liquid crystal apparatus, or in the case where a plurality of image signal lines are required to handle respective colors of an RGB color image signal, at least one image signal line has to cross another image signal line somewhere in the path to sampling switches. That is, it is impossible to produce wirings for all image signal lines using only a thin metal film at the same layer level.
Therefore, a interconnecting line (first wiring) is formed using a polysilicon film at a different layer separated by an interlayer insulating film from the thin metal film. More specifically, one wiring includes a second wiring made of a thin metal film and disposed at a crossing point. Another wiring includes a first wiring made of a thin polysilicon film extending at a different layer and crossing below or above the second wiring via an interlayer insulating film, wherein the first wiring is electrically connected to a part of the wiring made of thin metal film via contact holes formed, at both sides of the crossing point, in the interlayer insulating film.
If only a part, which crosses another wiring, is constructed in the form of a first wiring made of thin polysilicon film, and the other parts are constructed in the form of main wirings made of a thin metal film which are connected to each other via the first wirings as described above, then the first wiring made of the thin polysilicon film has a very small length, and thus the existence of the relay line made of the thin polysilicon film does not cause the image signal line to have no significant increases in the overall resistance and time constant that can cause a problem to occur during practical applications.
Problems to be Solved by the Invention
To meet the general requirement for improved image quality, the driving frequency of liquid crystal apparatus of XGA or SXGA type becomes increasingly higher. With the increase in the driving frequency, the number of serial-parallel converted phases becomes large. More specifically, 24 phases are employed recently.
However, to handle such a large number of serial-parallel convertion phases, it is required that a correspondingly great number of image signal lines to be disposed in parallel. As a result, the interconnecting lines made of the thin polysilicon film become longer. Because the resistance of the wiring increases in proportion to the length of the wiring, the resistance of the interconnecting lines becomes larger. As a result, the image signal lines have a large resistance and a large time constant which result in degradation in the image quality. More specifically, an increase in the resistance or the time constant of image signal lines causes the image signal to have fluctuations via coupling capacitance or causes the image signal on the previous line (column) to be written onto the next line (column), and thus a ghost or crosstalk occurs.
To avoid the above problem, if the interconnecting lines in the scaling area or periphery area are formed of a thin metal film which is not used in the pixel area, the efficiency of the production process based on the planar technology becomes low. As a result, the production cost becomes high and the fundamental advantages of the liquid crystal apparatus of the type including built-in peripheral circuits are lost.
In view of the above, it is an object of the present invention to provide an electrooptical apparatus, such as a liquid crystal apparatus of the type including a built-in peripheral circuit, in which the resistance of input/output wirings in the peripheral circuit is reduced by effectively using thin films forming pixels, thereby making it possible to display a high-quality image.
Means for Solving the Problems.
According to a first aspect of the present invention, to solve the above problems, there is provided an electrooptical apparatus including an electrooptical material disposed between a pair of substrates wherein, on one of the substrates, there are provided: a plurality of pixel electrodes arranged in a matrix fashion; a plurality of thin-film transistors that drive the plurality of pixel electrodes, respectively; a plurality of data lines connected to the plurality of thin-film transistors, respectively, and a plurality of scanning lines connected to the plurality of thin-film transistors, the plurality of data lines and the plurality of scanning lines crossing each other, a light blocking film disposed such that at least a channel region of each of the plurality of thin-film transistors is covered with the light blocking film; at least a peripheral circuit for supplying an image signal to the data lines; and peripheral wirings that input and output predetermined types of signals including the image signal to and from the peripheral circuit; wherein the peripheral wiring includes a first wiring having a first conductive film which is the same conductive film as the light blocking film and a second wiring including at least one of conductive films constituting the thin-film transistors, the data lines, and the scanning lines.
In the electrooptical apparatus according to the first aspect of the invention, the light blocking film is disposed such that at least the channel region of each of the plurality of thin-film transistors is covered with the light blocking film when viewed from the side of the one of substrates. Therefore, the channel region of each thin-film transistor is prevented by the light blocking film from being exposed to light, such as a reflected light ray coming from the side of the one of substrates, thereby preventing the thin-film transistors from being degraded in characteristics by the reflected light. In particular, in the present invention, the peripheral wirings include an wiring made of a conductive film (for example the thin film forming the data lines) which is one of a plurality of thin-film layers constituting the thin-film transistors, the data lines, and the scanning lines, and also include an wiring made of the first conductive film.
If the first conductive film is made of an electrically-conductive and refractory metal film including Ti (titanium), Cr (chromium), W (tungsten), Ta (tantalum), Mo (molybdenum), or Pb (lead), then the wiring resistance of the peripheral wiring is greatly reduced. In this technique, the first conductive film serves not only as a film for preventing the thin-film transistors from being exposed to light, but also as a peripheral wiring, and thus the structure and the production process can be simplified.
Therefore, various signals, including an image signal, can be input and output to and from the peripheral circuits via the peripheral wirings that have low resistance. Therefore, the driving frequency of the electrooptical apparatus can be increased or the number of serial-parallel conversion phases or the number of image signals which are input in parallel can be increased without causing voltage fluctuations, ghosts, or crosstalk due to capacitive coupling associated with the peripheral wirings such as image signal lines, which are problems in the conventional technique, thereby ensuring that a high-quality image is displayed.
In this mode, of the electrooptical apparatus according to the first aspect of the invention wherein the first wiring include the first conductive film and a second conductive film which is at least one of conductive films constituting the thin film transistors, the data lines and the scanning lines, and the second wiring include a third conductive film which is at least one of conductive films constituting the thin film transistors, the data lines, and the scanning lines and is different from the second conductive film.
In one mode of the electrooptical apparatus according to the first aspect of the invention, the peripheral wirings include the first wiring made of the first conductive film and the second conductive film, the second conductive film being made of a conductive film, which is one of the plurality of thin-film layers constituting the thin film transistors, the data lines and the scanning lines, the second wiring being made of the third conductive film.
In this mode, the first wiring of the peripheral wiring is made of the first conductive film and the second conductive film. The second wiring of the peripheral wiring is made of the third conductive film. Therefore, when the third conductive film is made of a thin film layer having a low resistance such as a metal film, and the second conductive film is made of a thin film such as a polysilicon film having a higher resistance than the first conductive film, the overall resistance of the peripheral wiring becomes lower by an amount corresponding to the reduction in the resistance of the second wiring achieved by the existence of the first conductive film compared with a combination of two types of conventional peripheral wirings made of the third and second conductive films, respectively, into a single layer structure, which cross each other somewhere. For example, when the second conductive film is formed of a polysilicon film and the first conductive film is formed of a refractory metal film having a high conductivity including Ti, Cr, W, Ta, Mo, or Pb, the resistance of the first wiring, measured along the wiring, is dominated by the sheet resistance of the first conductive film. Thus, it becomes possible to greatly reduce the resistance of the first wiring compared with the first wiring formed of only a single layer of polysilicon according to the conventional technique. Furthermore, in the present invention, the resistance of the second wiring can be reduced by employing the third conductive film such as Al (aluminum). Thus, the peripheral wiring including a first wiring and a second wiring electrically connected in series to each other has a low enough resistance.
Furthermore, the peripheral wiring has a redundant structure in which even if either a part formed of the thin polysilicon film or a part formed of the third conductive film of the first wiring is broken due a foreign particle or the like, the electrical conduction is still maintained via the remaining part. Since the first wiring that has the small resistance is formed using the first conductive film, which is also used to form pixels, and also using the first conductive film which is also used to protect the TFTs from light, the first wiring according to the present invention can be produced without causing a significant reduction in the production efficiency of the production process of the electrooptical apparatus with a planar structure. Thus, it is possible to achieve fundamental advantages of the electrooptical apparatus of the type including built-in peripheral circuits.
In the peripheral wiring including the first wiring and the second wiring according to the present invention, the second wiring made of the same film as the third conductive film may also be formed into a two-layer or three-layer structure by adding a redundant wiring. Such a multilayer wiring still includes the second wiring according to the invention. Furthermore, an additional redundant wiring may be added to the first wiring made of the same film as the second conductive film and the first conductive film so as to obtain an wiring structure including three or more layers. Such a multilayer wiring still includes a two-layer wiring according to the invention.
In the mode of the electrooptical apparatus according to the first aspect of the invention in which the peripheral wiring includes the first wiring, the second conductive film may have a resistance higher than that of the third conductive film.
In this structure, the third conductive film, such as aluminum, has the lowest resistance of all thin films used to form the thin-film transistors, and the second conductive film, such as the low-resistance polysilicon film, has the next lowest resistance of all thin films used to form the thin-film transistors. As a result, the overall resistance of the peripheral wiring becomes lower by an amount of reduction in the resistance of the first wiring achieved by employing the third conductive film having a high conductivity compared with the case where peripheral wirings are formed of third and second conductive films in a single-layer structure crossing each other at different layer levels, according to the conventional technique.
In a mode of the electrooptical apparatus according to the first aspect of the invention in which the peripheral wirings include the first wiring, the electrooptical apparatus further includes a first interlayer insulating film disposed between the third conductive film and the thin-film transistors; and a second interlayer insulating film disposed between the third conductive film and the second conductive film; wherein the first wiring includes a interconnecting line which is electrically connected to a part of the second wiring and which crosses another part of the second wiring in a three-dimensional fashion via the first or second interlayer insulating films.
In this mode, the interconnecting line is electrically connected to a part of the second wiring and crosses another part of the second wiring in a three-dimensional fashion via the first or second interlayer insulating film (that is, the interconnecting line passes over or under another part of the single-layer wiring). That is, because peripheral wirings must cross each other somewhere, it is impossible to dispose all peripheral wirings at the same layer level. This problem is solved by employing a interconnecting line. That is, the interconnecting line makes it possible to dispose peripheral wirings into any desired pattern.
In the mode of the electrooptical apparatus according to the first aspect of the invention in which the first wiring includes the interconnecting line, the peripheral wirings may include an image signal line for supplying the image signal from an external input terminal; and the peripheral circuit may include a sampling circuit for sampling the image signal, a data line driving circuit for driving the sampling circuit with predetermined timing thereby supplying the image signal on the image signal line to the plurality of data lines via the sampling circuit, and a scanning line driving circuit for driving the scanning lines.
This allows the image signal line, which has to cross another peripheral wiring somewhere and which could not be disposed in a desired manner if it were disposed at the same layer level, to be disposed in any desired pattern via a interconnecting line.
In the mode of the electrooptical apparatus according to the first aspect of the invention in which the peripheral wirings include the image signal line, the image signal may be serial-parallel converted to N phases (where N is an integer equal to or greater than 2) and there may be provided N image signal lines, and the N image signal lines may include a interconnecting line at a location where some of the N image signal lines cross to each other.
In this structure, increases in the resistance and time constant of the interconnecting line are minimized even when long interconnecting lines are required to handle a large number (N) of serial-parallel conversion phases, or to handle a large number of image signals which are input in parallel as is the case with RGB color image signals, in particular compared with the case where interconnecting lines are formed of a single layer of a thin polysilicon film according to the conventional technique.
In the mode of the electrooptical apparatus according to the first aspect of the invention in which the peripheral wirings include the image signal line, the electrooptical apparatus may further include a plurality of sampling circuit driving signal lines that supply a sampling circuit driving signal from the data line driving circuit to the sampling circuit, and at least a part of the sampling circuit driving signal lines which crosses any of the image signal lines may be made of the interconnecting line.
This technique makes it possible to form sampling circuit driving signal lines extending from the data line driving circuit to the sampling circuit using interconnecting lines disposed at locations where they cross for example an image signal line. Furthermore, this technique allows the wiring layout to be designed in a more flexible manner. Still furthermore, increases in the resistance and time constant of the sampling circuit driving signal lines can be reduced compared with the case where interconnecting lines of the sampling circuit driving signal lines are formed of a single layer of a thin polysilicon film according to the conventional technique.
In the mode of the electrooptical apparatus according to the first aspect of the invention in which the peripheral wirings include the first wiring, the second conductive film and the first conductive film both constituting the two-layer wiring may be electrically connected to each other via a contact hole formed in the first interlayer insulating film.
This technique makes it possible to obtain a high-reliability first wiring whose layers are electrically connected to each other via a contact hole. The contact hole for this purpose may be formed relatively easily using the process for producing the pixel TFTs.
In the mode of the electrooptical apparatus according to the first aspect of the invention in which the peripheral wirings include the two-layer wiring, the third conductive film may be made of a thin metal film forming the data lines connected to the source or drain of the thin-film transistors, and the second conductive film may be made of a thin polysilicon film forming the scanning lines including gate electrodes of the thin-film transistors.
In this case, because the second wiring is formed of the thin metal film, such as aluminum, the single-layer wiring has a low resistance. Although the part formed of the thin polysilicon film has a resistance 200 times greater than that of the thin metal film, that part has a parallel path formed of the first conductive film with electrical conductivity, and thus the overall resistance of the first wiring is much smaller than the resistance of the thin polysilicon film. If the first conductive film is made of metal, including at least one of Ti, Cr, W, Ta, Mo, or Pb or a metal silicide, the overall resistance and time constant can be reduced to several tenths (for example, about xc2xd or ⅓) of those that would be obtained with a single-layer of thin polysilicon film.
In the mode of the electrooptical apparatus according to the first aspect of the invention in which the peripheral wirings include the two-layer wiring, the electrooptical apparatus may further include a sealing material for enclosing the electrooptical material between the pair of substrates, and at least three films including the first conductive film, the second conductive film, and the light blocking film may be disposed in a multilayer fashion in a sealing area, in contact with the sealing material, on the one of substrate, around the periphery of the electrooptical material, and furthermore, the leading wirings of the data lines and scanning lines extending across the sealing area may be formed of at least one of the above-described three films.
In this structure, the electrooptical material is enclosed by the sealing material between the pair of substrates such that a so-called electrooptical cell is formed. Because at least three films including the third conductive film, the second conductive film, and the first conductive film are disposed in a multilayer fashion in the sealing area around the periphery of the electrooptical material, it is possible to minimize the variation in the gap, including the effects of various thin films, between the two substrates over the entire sealing area around the electrooptical material. Thus, it becomes possible to more precisely control the gap of the liquid crystal cell when the gap is controlled by the sealing material containing gap materials with a particular diameter. Furthermore, by using the leading wirings of the data lines and scanning lines, which are formed of at least one of the three films and which extend across the sealing area, it is possible to supply signals into the image displaying area without encountering any problems.
In the mode of the electrooptical apparatus according to the first aspect of the invention in which the three-layer film is disposed in the sealing area, the healing wirings may each include a two-layer or three-layer wiring whose layers are made of at least two of the three films, respectively, wherein the layers are electrically connected to each other via a contact hole. This structure allows a reduction in the resistance of the leading wirings.
Alternatively, the leading wirings may each include a single-layer wiring made of one of the three films, and the other two films of the three films may be dummy wirings which do not serve as an wirings in the sealing region. In this structure, the gap in the sealing area between the two substrates is determined by the thickness of the dummy wirings, and thus it is possible to relatively easily minimize the variation in the gap.
In the mode of the electrooptical apparatus according to the first aspect of the invention in which the peripheral wirings include the first wiring, the first wiring may have such a structure that the part made of the first conductive film is covered with the part made of the second conductive film when viewed from the side of the other one of the pair of substrates.
In this mode, because the part, made of the first conductive film, of the two-layer wiring is covered with the part made of the second conductive film, the single-layer wiring such as an image signal line crossing the part made of the first conductive film has a less capacitive coupling with the part made of the first conductive film, and thus the increase in the time constant associated with the single-layer wiring causes by the capacitive coupling can be suppressed. In particular, when the second conductive layer is disposed between the first conductive film and the third conductive film, it is possible to suppress the increase in the capacitive coupling between the first conductive film and the first conductive film in the structure in which the first conductive film is employed in the first wiring. This makes it possible to effectively prevent degradation in the image signal at the single-layer wiring of the image signal line.
In the mode of the electrooptical apparatus according to the first aspect of the invention in which the part made of the first conductive film is covered with the part made of the second conductive film, in the first wiring, the part made of the first conductive film may have an wiring width smaller than the part made of the second conductive film.
This technique ensures that the increase in capacitive coupling between the first conductive film and the third conductive film is suppressed.
According to a second aspect of the present invention, to solve the above problems, there is provided an electrooptical apparatus including an electrooptical material disposed between a pair of substrates wherein, on one of the substrates, there are provided: a plurality of scanning lines; a plurality of data lines; thin-film transistors connected to the plurality of scanning lines, respectively, and also to the plurality of data lines, respectively; pixel electrodes connected to the respective thin-film transistors; an electrically-conductive light blocking film disposed such that at least the channel region of each thin-film transistor is covered with the light blocking film when viewed from the side of the one of substrates; a plurality of image signal lines that supply an image signal; and a sampling circuit that samples the image signals supplied via the plurality of image signal lines and supplies the resultant signals to the plurality of data lines, respectively; wherein at least a part of each of interconnecting lines connecting the image signal lines to the sampling circuit is made of a third conductive film which is made of the same layer as the light blocking film.
In the electrooptical apparatus according to the second aspect of the invention, because at least a part of each of interconnecting lines connecting the image signal lines to the sampling circuit is made of the third conductive film, it is possible to obtain a lower resistance for the interconnecting lines compared with the case where, of thin film layers forming the thin-film transistors, the data lines, and the scanning lines, the second conductive film having a lower conductivity than the first conductive film is selected as the material of the interconnecting lines. If the third conductive film is formed of, for example, a refractory metal film having electrical conductivity, it is possible to greatly reduce the wiring resistance of the interconnecting lines. In this case, the first conductive film serves not only as a film that prevents the thin-film transistors from being exposed to light but also as a peripheral wiring, and thus the construction and the production process can be simplified.
In this technique, because the image signals are input to the sampling circuit via the interconnecting lines having low resistance, the driving frequency of the electrooptical apparatus can be increased, or the number of serial-parallel converted phases, or the number of image signals which are input in parallel can be increased without causing voltage fluctuations, ghosts, or crosstalk due to capacitive coupling associated with the interconnecting lines of, for example, image signal lines, which are problems in the conventional technique, thereby ensuring that a high-quality image is displayed.
In one mode of the electrooptical apparatus according to the second aspect of the invention, at least a part of sampling circuit driving signal lines that supply a sampling circuit driving signal to the sampling circuit is made of the first conductive film.
In this mode, because at least a part of sampling circuit driving signal lines is made of the first conductive film with electrical conductivity, it is possible to obtain a lower resistance for the sampling circuit driving signal lines compared with the case where, of thin film layers forming the thin-film transistors, the data lines, and the scanning lines, the second conductive film that has a lower conductivity than the first conductive film is selected as the material of the sampling circuit driving signal lines. Because the sampling circuit drive signals are input to the sampling circuit via sampling circuit driving signal lines having low resistance, it is possible to display a high-quality image.
To solve the problems described earlier, the invention provides a first method of producing an electrooptical apparatus including an electrooptical material disposed between a pair of substrates wherein, on one of the substrates, there are provided: a plurality of scanning lines; a plurality of data lines; thin-film transistors connected to the plurality of scanning lines, respectively, and also to the plurality of data lines, respectively; pixel electrodes connected to the respective thin-film transistors; an electrically-conductive light blocking film disposed such that at least the channel region of each thin-film transistor is covered with the light blocking film when viewed from the side of the one of substrates; a plurality of image serial lines that supply an image signal; and a sampling circuit that samples the image signals supplied via the plurality of image signal lines and supplies the resultant signals to the plurality of data lines, respectively; the method including the steps of: forming the light blocking film and first interconnecting lines that connect the image signal lines to the sampling circuit using the same material; forming a first interlayer insulating film on the first interconnecting lines and the light blocking film; forming the scanning lines on the first interlayer insulating film and also forming a second interconnecting line connected to the first interconnecting line via a contact hole formed in the first interlayer insulating film; forming a second interlayer insulating film on the scanning lines and the second interconnecting line; and forming the data lines connected to the thin-film transistors via contact holes formed in the second interlayer insulating film and also forming the image signal lines connected to the second interconnecting line.
In the first method of producing the electrooptical apparatus according to the invention, the light blocking film and the first interconnecting lines that connect the image signal lines to the sampling circuit are formed using the same material. This allows simplification in the production process. Then the first interlayer insulating film is formed on the first interconnecting lines and the light blocking film, and scanning lines are formed on this first interlayer insulating film. The second interconnecting line is then formed such that it is connected to the first interconnecting line via a contact hole formed in the first interlayer insulating film. The second interlayer insulating film is then formed on the scanning lines and the second interconnecting line. After that, the data lines connected to the thin-film transistors via contact holes formed in the second interlayer insulating film and also the image signal lines connected to the second interconnecting lines are formed. Thus, in this technique, because the image signals are input to the sampling circuit via the interconnecting lines that have low resistance, it is possible to produce an electrooptical apparatus capable of displaying a high-quality image, even if the driving frequency of the electrooptical apparatus is increased, or the number of serial-parallel conversion phases, or the number of image signals which are input in parallel is increased.
To solve the problems described earlier, the invention also provides a second method of producing an electrooptical apparatus including an electrooptical material disposed between a pair of substrates wherein, on one of the substrates, there are provided: a plurality of scanning lines; a plurality of data lines; thin-film transistors connected to the plurality of scanning lines, respectively, and also to the plurality of data lines, respectively; pixel electrodes connected to the respective thin-film transistors; an electrically-conductive light blocking film disposed such that at least the channel region of each thin-film transistor is covered with the light blocking film when viewed from the side of the one of substrates; a plurality of image signal lines that supply an image signal; and a sampling circuit that samples the image signals supplied via the plurality of image signal lines and supplies the resultant signals to the plurality of data lines, respectively; the method including the steps of forming the light blocking film and first interconnecting lines that connect the image signal lines to the sampling circuit using the same material; forming a first interlayer insulating film on the first interconnecting lines and the light blocking film; successively forming a plurality of films into a multilayer structure on the first interlayer insulating film, the plurality of films including a semiconductor layer acting as a source and drain of each thin-film transistor, a gate insulating film, and a gate electrode; forming a second interlayer insulating film on the gate electrode; and forming the data lines connected to the thin-film transistors via contact holes formed in the second interlayer insulating film and also forming image signal lines connected to the first interconnecting lines via contact holes formed in the first and second interlayer insulating films.
In the second method of producing the electrooptical apparatus according to the invention, the light blocking film and the first interconnecting lines for connecting the image signal lines to the sampling circuit are formed using the same material. This allows simplification in the production process. After that, the first interlayer insulating film is formed on the first interconnecting lines and the light blocking film. Furthermore, the semiconductor layer acting as a source and drain of each said thin-film transistor, the gate insulating film, and the gate electrode are successively formed into the multilayer structure on the first interlayer insulating film. The second interlayer insulating film is then formed on the gate electrode. Furthermore, the data lines connected to the thin-film transistors via contact holes formed in the second interlayer insulating film are formed. After that, the image signal lines connected to the first interconnecting line via contact holes formed in the first and second interlayer insulating films are formed. Thus, in this technique, because the image signals are input via the interconnecting lines that have low resistance, it is possible to produce an electrooptical apparatus capable of displaying a high-quality image, even if the driving frequency of the electrooptical apparatus is increased, or the number of serial-parallel conversion phases, or the number of image signals which are input in parallel is increased.